Racetrack layout for radio frequency shielding

ABSTRACT

Aspects of the present disclosure relate to determining a layout of a racetrack that forms part of an RF isolation structure of a packaged module and the resulting RF isolation structures. The racetrack layout can be determined based on identifying low radiating areas of a module and/or areas of a module that are less sensitive to external radiation. The racetrack can be disposed below a surface of a module on which a radio frequency component is disposed. The racetrack and a conductive layer over the radio frequency component can form part of a radio frequency isolation structure around the RF component.

RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.13/939,066, filed Jul. 10, 2013, titled “RACETRACK DESIGN IN RADIOFREQUENCY SHIELDING APPLICATIONS,” which claims the benefit of priorityunder 35 U.S.C. §119(e) of U.S. Provisional Patent Application No.61/671,594, filed Jul. 13, 2012, titled “RACETRACK DESIGN IN RADIOFREQUENCY SHIELDING APPLICATIONS”, the disclosures of each which areherein incorporated by reference in their entireties.

BACKGROUND

Technical Field

The present disclosure relates to packaged semiconductor structures and,more particularly, to structures configured to provide radio frequency(RF) isolation.

Description of the Related Technology

Packaged semiconductor modules can include integrated shieldingtechnology. To form a shield, which can be referred to as a “Faradaycage,” a top conductive layer can be electrically connected to aracetrack by other conductive features. A racetrack can be a conductivefeature in the substrate along a periphery of the substrate. Theracetrack can be configured at a ground potential. The racetrack can beelectrically connected to conductive features in a different layer ofthe substrate by a plurality of vias. One or more layers in thesubstrate can each include a racetrack.

For instance, the racetrack can be electrically connected to a groundplane and form a portion of an electrical connection between the topconductive layer and the ground plane. The racetrack can function aspart of the shield itself. However, the racetrack consumes area in thepackaged module. At the same time, the racetrack can affect a strengthof the ground connection of the shield.

SUMMARY OF CERTAIN INVENTIVE ASPECTS

The innovations described in the claims each have several aspects, nosingle one of which is solely responsible for its desirable attributes.Without limiting the scope of this invention, some prominent featureswill now be briefly discussed.

One aspect of this disclosure is a packaged module that includes asubstrate configured to receive at least one component, a radiofrequency (RF) component coupled to a major surface of the substrate,and an RF isolation structure. The RF isolation structure includes aracetrack disposed below the major surface of the substrate, aconductive layer disposed above the RF component, and one or moreconductive features disposed between the racetrack and the conductivelayer. The one or more conductive features are configured to provide atleast a portion of an electrical connection from racetrack to theconductive layer. The racetrack is configured at a ground potential anddisposed around the RF component in the substrate. The racetrack has abreak and/or a narrowed section.

The break or the narrowed section can be disposed in a low radiatingarea of the packaged module. In certain implementations, the lowradiating area of the packaged module can be associated with a minimumradiation around the perimeter of the packaged module. According to someimplementations, the low radiating area can have a low activity factorrelative to other areas of the packaged module.

The racetrack can have at least one break and at least one narrowedsection in certain implementations. In accordance with someimplementations, the racetrack can include a plurality of narrowedsections. The racetrack can have a plurality of breaks according to anumber of implementations.

The racetrack can be disposed along a periphery of the packaged module,in accordance with a number of implementations. In a variousimplementations, the one or more conductive features include wirebonds.

The RF isolation structure can also include an additional racetrackdisposed below the major surface of the substrate and electricallyconnected to the racetrack by a plurality of the vias, according tocertain implementations. The additional racetrack can have a breakand/or a narrowed section.

According to various implementations, the RF component can include apower amplifier.

Another aspect of this disclosure is a packaged module that includes asubstrate configured to receive at least one component, a radiofrequency (RF) component coupled to a major surface of the substrate,and an RF isolation structure. The RF isolation structure includes aracetrack disposed below the major surface of the substrate and aroundthe perimeter of the RF component. The racetrack is configured at aground potential. The racetrack has a first width that is narrower in asection corresponding to a low radiating area of the packaged modulethan a second width in a section of the racetrack corresponding to a hotspot of the packaged module. The RF isolation structure also includes aconductive layer disposed above the RF component and conductive featuresdisposed between the racetrack and the conductive layer. The conductivefeatures are configured to provide at least a portion of an electricalconnection from the racetrack to the conductive layer.

Another aspect of this disclosure is a wireless device that includes anantenna configured to facilitate transmitting and/or receiving aradio-frequency (RF) signal, a packaged module in communication with theantenna, and an other electronic module in communication with thepackaged module. The packaged module includes a substrate configured toreceive a plurality of components; a radio frequency (RF) componentcoupled to a major surface the substrate. The packaged module alsoincludes a racetrack in the substrate disposed around the RF componentbelow the major surface of the substrate. The racetrack is configured ata ground potential. The racetrack has a section with break or a widththat is narrower than other portions of the racetrack. The packagedmodule also includes a conductive layer disposed above the RF component.The conductive layer is electrically connected to the racetrack suchthat the racetrack and the conductive layer form at least a portion ofan RF isolation structure around the RF component.

In certain implementations, the section including the break or thenarrow width can be disposed in a low radiating area of the packagedmodule. According to some of these implementations, the RF component canbe configured to emit less electromagnetic radiation to the lowradiating area of the packaged module than to other areas of thepackaged module. Alternatively or additionally, the packaged module canbe configured to receive less electromagnetic radiation at the lowradiating area of the packaged module from the other electronic modulethan at other areas of the packaged module.

The racetrack can have one or more breaks and one or more narrowedsections.

According to some implementations, the packaged module can also includewirebonds configured to provide at least a portion of an electricalconnection between the racetrack and the conductive layer, in which theRF isolation structure including the wirebonds.

Yet another aspect of this disclosure is a method of determining aracetrack layout. The method includes identifying low radiating areas ofa module that includes a radio frequency (RF) component coupled to amajor surface of a substrate, and determining a racetrack layout basedon identifying the low radiating areas of the module. The racetrack isdisposed below the major surface of the substrate and is included in anRF isolation structure around the RF component. The RF isolationstructure also includes a conductive layer above the RF component.

According to certain implementations, determined racetrack layout caninclude a section with a reduced width in an identified low radiatingarea of the module relative to a width in other sections of thedetermined racetrack layout. Alternatively or additionally, thedetermined racetrack layout can include a break in an identified lowradiating area of the module.

In some implementations, the RF isolation structure can also includewirebonds configured to provide at least a portion of an electricalconnection between the racetrack and the conductive layer above the RFcomponent.

In accordance with a number of implementations, the determined racetracklayout can be included in at least two separate layers in the substrate.

According to various implementations, the method can also includeobtaining electromagnetic interference data for the module, andidentifying the low radiating areas based on the obtainedelectromagnetic interference data. In some of these implementations,obtaining electromagnetic interference data can include obtainingelectromagnetic interference data for at least two different modes ofoperation of the RF component.

For purposes of summarizing the disclosure, certain aspects, advantagesand novel features of the inventions have been described herein. It isto be understood that not necessarily all such advantages may beachieved in accordance with any particular embodiment of the invention.Thus, the invention may be embodied or carried out in a manner thatachieves or optimizes one advantage or group of advantages as taughtherein without necessarily achieving other advantages as may be taughtor suggested herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is top plan view of an illustrative packaged module.

FIG. 1B shows a cross section of the packaged module of FIG. 1A alongthe line 1B-1B of FIG. 1A

FIG. 2 shows a process that can be implemented to fabricate a packagedmodule that includes a die having an integrated circuit (IC).

FIGS. 3A1 and 3A2 show front and back sides of an example laminate panelconfigured to receive a plurality of dies for formation of packagedmodules.

FIGS. 3B1 to 3B3 show various views of a laminate substrate of the panelconfigured to yield an individual module.

FIG. 3C shows an example of a fabricated semiconductor wafer having aplurality of dies that can be singulated for mounting on the laminatesubstrate.

FIG. 3D depicts an individual die showing example electrical contactpads for facilitating connectivity when mounted on the laminatesubstrate.

FIGS. 3E1 and 3E2 show various views of the laminate substrate beingprepared for mounting of example surface-mount technology (SMT) devices.

FIGS. 3F1 and 3F2 show various views of the example SMT devices mountedon the laminate substrate.

FIGS. 3G1 and 3G2 show various views of the laminate substrate beingprepared for mounting of an example die.

FIGS. 3H1 and 3H2 show various views of the example die mounted on thelaminate substrate.

FIGS. 3I1 and 3I2 show various views of the die electrically connectedto the laminate substrate by example wirebonds.

FIGS. 3J1 and 3J2 show various views of wirebonds formed on the laminatesubstrate and configured to facilitate electromagnetic (EM) isolationbetween an area defined by the wirebonds and areas outside of thewirebonds.

FIG. 3K shows a side view of molding configuration for introducingmolding compound to a region above the laminate substrate.

FIG. 3L shows a side view of an overmold formed via the moldingconfiguration of FIG. 3K.

FIG. 3M shows the front side of a panel with the overmold.

FIG. 3N shows a side view of how an upper portion of the overmold can beremoved to expose upper portions of the EM isolation wirebonds.

FIG. 3O shows a photograph of a portion of a panel where a portion ofthe overmold has its upper portion removed to better expose the upperportions of the EM isolation wirebonds.

FIG. 3P shows a side view of a conductive layer formed over the overmoldsuch that the conductive layer is in electrical contact with the exposedupper portions of the EM isolation wirebonds.

FIG. 3Q shows a photograph of a panel where the conductive layer can bea spray-on metallic paint.

FIG. 3R shows individual packaged modules being cut from the panel.

FIGS. 3S1 to 3S3 show various views of an individual packaged module.

FIG. 3T shows that one or more of modules that are mounted on a wirelessphone board can include one or more features as described herein.

FIG. 4A shows a process that can be implemented to install a packagedmodule having one or more features as described herein on a circuitboard such as the phone board of FIG. 3T.

FIG. 4B schematically depicts the circuit board with the packaged moduleinstalled thereon.

FIG. 4C schematically depicts a wireless device having the circuit boardwith the packaged module installed thereon.

FIG. 4D schematically depicts an electronic device having a radiofrequency (RF) isolation structure.

FIG. 5A is a flow diagram of an illustrative process of determining aracetrack layout according to an embodiment.

FIG. 5B is a flow diagram of an illustrative process of determining aracetrack layout according to another embodiment.

FIGS. 6A to 6G show cross sections of racetrack layouts in a substratealong the line 140-140 in FIG. 1B in accordance with certainembodiments.

Features of the apparatus, systems, and methods will be described withreference to the drawings summarized above. Throughout the drawings,reference numbers are re-used to indicate correspondence betweenreferenced elements. It will be understood that all drawings are notnecessarily to scale. The drawings, associated descriptions, andspecific implementations are provided for illustrative purposes and arenot intended to limit the scope of the disclosure.

DETAILED DESCRIPTION OF SOME EMBODIMENTS

An RF isolation structure around an RF component can isolate the RFcomponent from external radiation and/or isolate an external componentfrom radiation emitted by the RF component. The RF isolation structurecan include a racetrack, conductive features, and a conductive layerdisposed above an RF component. In some implementations, the racetrackcan provide part of an electrical connection between a ground plane andthe top conductive layer. Conductive features, such as wirebonds, canprovide at least a portion of an electrical connection between theracetrack and the conductive layer disposed above the RF component. Itcan be desirable to have a strong ground connection to the RF isolationstructure. The strength of the RF isolation structure can be based on astrength of the ground connection. A thicker racetrack can provide astronger ground connection. In previous designs, a continuous racetrackhaving a uniform width was included along a periphery of a packagedmodule. Such racetracks consumed die area and increased costs of thepackaged module.

In this disclosure, it is recognized that a racetrack layout can bedetermined based on electromagnetic interference (EMI) data, such as EMIprobing data and/or near field scan data. Particular features related toisolation associated with RF signals are also recognized in thisdisclosure. One or more features described herein relate to selectivelynarrowing and/or removing portions of a racetrack such that an RFisolation structure provides desired RF isolation without consumingexcess die area. For instance, EMI data from a particular environmentcan be obtained and a racetrack layout can be determined based on suchdata.

Generally described, aspects of this disclosure relate to determining alayout of a racetrack that that is part of an RF isolation structure.The racetrack layout can have a non-uniform width to match the relativestrength of the RF isolation structure in selected areas with RFisolation needs of a module that includes at least one RF component.

From simulation and/or EMI data, locations of “hot spots” and/or “lowradiating areas” of a packaged module can be determined. A “hot spot”can be an area of the packaged module that emits a relatively highamount of electromagnetic radiation and/or an area of the packagedmodule that receives a relatively high amount of externalelectromagnetic radiation. A “low radiating area” can be an area of thepackaged module that emits a relatively low amount of electromagneticradiation and/or an area of the packaged module that receives arelatively low amount of external electromagnetic radiation.

Based on the locations of the hot spots and/or low radiating areas, theracetrack can include a break in one or more selected areas of thepackaged module without significantly degrading the EMI performance ofthe RF isolation structure. Alternatively or additionally, based on thelocations of the hot spots and/or low radiating areas, a width of theracetrack that is part of the RF isolation structure can be narrowed inone or more selected areas of the packaged module without significantlydegrading the EMI performance of the RF isolation structure. Morespecifically, the racetrack can include a break and/or a narrowedsection in a low radiating area of the packaged module.

Alternatively or additionally, the sensitivity of locations of thepackaged module to external radiation can be determined. Based on thesensitivity data, the racetrack can include a break and/or a sectionwith a narrowed width in one or more selected areas.

By including a break in the racetrack and/or narrowing sections of theracetrack, the RF isolation structure can consume less area in one ormore layers of a substrate. As a result, the packaged module can besmaller, less expensive, consume less power, or any combination thereof.Tailoring racetrack layout to particular RF isolation needs can reducethe total amount of metal used to manufacture the packaged modulewithout significantly degrading EMI performance. This can reduce thetotal cost of a packaged module that includes the racetrack. Inproduction, these cost savings can be significant when a large number ofpackaged modules are manufactured.

Described herein are various examples of systems, apparatus, devicesstructures, materials and/or methods related to fabrication of packagedmodules having a radio-frequency (RF) circuit and wirebond-basedelectromagnetic (EM) isolation structures. Although described in thecontext of RF circuits, one or more features described herein can alsobe utilized in packaging applications involving non-RF components.Similarly, one or more features described herein can also be utilized inpackaging applications without the EM isolation functionality. It willalso be understood that one or more features described herein can beapplied to isolation structures that do not include wirebonds.

For the purpose of description, it will be understood that RF-isolationcan include keeping RF signals or noise from entering or leaving a givenshielded area. Thus, for the purpose of description, it will beunderstood that the terms isolation and shielding can be usedinterchangeably as appropriate. For example, an RF component beingshielded can include a situation where some or substantially all of anRF signal from another source is being blocked from reaching the RFcomponent. As another example, an RF component being isolated caninclude a situation where some or substantially all of an RF signal (forexample, noise or an actively generated signal) is being blocked fromreaching from another device. Unless the context indicates otherwise, itwill be understood that each of the terms shielding and isolation caninclude either or both of the foregoing functionalities.

FIG. 1A is top plan view of an illustrative packaged module 1. Thepackaged module 1 can include one or more circuit elements. In a numberof embodiments, the one or more circuit elements include an RF circuitelement. The packaged module 1 can include an RF isolation structurethat includes one or more racetracks. The packaged module 1 can be apackaged integrated circuit. The illustrated packaged module 1 includesa radio frequency (RF) isolation structure 2 and an RF component thatincludes a high band portion 3 and a low band portion 4. Although notillustrated in FIG. 1A for clarity, the packaged module 1 can includenumerous other structures.

The RF isolation structure 2 can function as a Faraday cage. The RFisolation structure 2 can include conductive features around at leastone RF component. In certain implementations, the conductive featuresabove the substrate can include a plurality of wirebonds 51 that incombination with a racetrack are configured to provide RF isolation.More details of the plurality of wirebonds 51 will be provided later,for example, with reference to FIGS. 3J1 and 3J2. In some otherimplementations, the conductive features can include other structures,such as a solid metal can.

The illustrated packaged module 1 is a packaged power amplifierintegrated circuit (IC) in which the high band portion 3 includes a highband power amplifier circuit and the low band portion 4 includes a lowband power amplifier circuit. Power amplifiers can be used to boost theamplitude of a relatively weak RF signal. Thereafter, the boosted RFsignal can be used for a variety of purposes, including, for example,driving an antenna, a switch, a mixer, a filter, or the like, or anycombination thereof in an RF system. In certain electronic systems, suchas multi-band systems, different power amplifier structures can be usedto amplify RF signals of different frequencies. In the illustratedconfiguration, the packaged module 1 includes the high band poweramplifier circuit for amplifying relatively high frequency RF signalsand the low band power amplifier circuit for amplifying relatively lowfrequency RF signals.

Although the packaged module 1 illustrates one example of a packaged ICthat can be used herein, the methods and apparatus described herein canbe implemented in connection with a variety of other isolationstructures in packaged modules.

FIG. 1B shows a cross section of the packaged module 1 along the line1B-1B of FIG. 1A and a system circuit board 9 under the packaged module1. The illustrated cross section shows a side view of the RF isolationstructure 2. As illustrated, the packaged module 1 includes a printedcircuit board 8, wirebonds 51, overmold structure 59, and a conductivelayer 71 formed over the overmold structure 59. The system board 9 caninclude a substrate system board substrate 5 and an electrical referenceplane 30, which can be a ground plane. The printed circuit board 8 canbe a substrate, such as a laminate substrate. The printed circuit board8 can include input output (I/O) pads (for example, ground contact pads29), a plurality of vias 6, and one or more racetracks 7. The pluralityof vias 6 and the one or more racetracks 7 can electrically connect theground contact pads 29 to wirebond pads 26, thereby electricallyconnecting the reference plane 30 to the wirebonds 51. The printedcircuit board 8 can also include a ground plane. The wirebonds 51 can bedisposed above the printed circuit board 8 in the orientation shown inFIG. 1B. Overmold structure 59 can encapsulate the wirebonds 51. Moredetail about the overmold structure 59 will be provided later, forexample, with reference to FIGS. 3L-3M. The wirebonds 51 can beelectrically connected to the conductive layer 71.

As illustrated, the RF isolation structure 2 of the packaged module 1includes the ground contact pads 29, the racetracks 7, the plurality ofvias 6, the wirebonds 51, and the conductive layer 71. For instance, theracetracks 7 can provide RF isolation from RF signals generated by RFcircuits within the RF isolation structure 2 and/or outside of the RFisolation structure 2. In the implementation shown in FIG. 1B, theracetrack 7 in combination with a plurality of vias 6 can block most ofthe power of an RF signal along sidewalls of the substrate of thepackaged module 1. The layout of the racetrack 7 can be determined inaccordance with one or more features described herein.

Although the illustrative cross section of FIG. 1B shows racetracks 7 inthree layers, it will be understood that one or more features describedherein can be applied to RF isolation structures that include aracetrack 7 in any suitable number of layers of the substrate. Forinstance, in other implementations, there can a single racetrack 7. Asanother example, in certain implementations there can be a racetrack 7in each of four or more layers. In implementations with a racetrack 7 intwo or more layers of metal routing in the substrate, the racetracks 7can be have the same layout and/or different layouts in differentlayers.

FIG. 2 shows a process 10 that can be implemented to fabricate apackaged module 1, such as a packaged module, having and/or by way ofone or more features as described herein. FIG. 2 shows various partsand/or stages of various operations associated with the process 10 ofFIG. 2.

In block 12 a of FIG. 2, a packaging substrate and parts to be mountedon the packaging substrate can be provided. Such parts can include, forexample, one or more surface-mount technology (SMT) components and oneor more singulated dies having integrated circuits (ICs). FIGS. 3A1 and3A2 show that in some embodiments, the packaging substrate can include alaminate panel 16. FIG. 3A1 shows the front side of the example laminatepanel 16; and FIG. 3A2 shows the back side of the example laminate panel16. The laminate panel 16 can include a plurality of individual modulesubstrates 20 arranged in groups that are sometimes referred to asarrays 18. Although four separate molded sections are shown in FIGS.3A1, 3A2, 3M, and 3Q, any of the features described in the applicationcan be applied to other suitable arrangements such as a single arraymold cap without breaks.

FIGS. 3B1-3B3 show front, side and back views, respectively, of anexample configuration of the individual module substrate 20. Forillustrative purposes, a boundary 22 can define an area occupied by themodule substrate 20 on the panel 16. Within the boundary 22, the modulesubstrate 20 can include a front surface 21 and a back surface 27. Shownon the front surface 21 is an example mounting area 23 dimensioned toreceive a die (not shown). A plurality of example contact pads 24 arearranged about the die-receiving area 23 so as to allow formation ofconnection wirebonds between the die and contact pads 28 arranged on theback surface 27. Although not shown, electrical connections between thewirebond contact pads 24 and the module's contact pads 28 can beconfigured in a number of ways. Also within the boundary 22 are two setsof example contact pads 25 configured to allow mounting of, for examplepassive SMT devices (not shown). The contact pads can be electricallyconnected to some of the module's contact pads and/or ground contactpads 29 disposed on the back surface 27. Also within the boundary 22 area plurality of wirebond pads 26 configured to allow formation of aplurality of EM-isolating wirebonds (not shown). The wirebond pads 26can be electrically connected to an electrical reference plane (such asa ground plane) 30. Such connections between the wirebond pads 26 andthe ground plane 30 (depicted as dotted lines 31) can be achieved in anumber of ways. For instance, as shown in FIG. 1B, a plurality of vias 6and/or one or more racetracks 7 can form at least part of the electricalconnection between the wirebond pads 26 and the ground plane 30. Thevias 6 and/or racetrack(s) 7 can form a portion of an RF isolationstructure 2 around an RF circuit in the module. In some embodiments, theground plane 30 may or may not be connected to the ground contact pads29 disposed on the back surface 27. In some other embodiments (notshown), a ground plane can alternatively or additionally be included inthe substrate of the module.

FIG. 3C shows an example fabricated wafer 35 that includes a pluralityof functional dies 36 awaiting to be cut (or sometimes referred to assingulated) into individual dies. Such cutting of the dies 36 can beachieved in a number of ways. FIG. 3D schematically depicts anindividual die 36 where a plurality of metalized contact pads 37 can beprovided. Such contact pads can be configured to allow formation ofconnection wirebonds between the die 36 and the contact pads 24 of themodule substrate (e.g., FIG. 3B1).

In block 12 b of FIG. 2, solder paste can be applied on the modulesubstrate to allow mounting of one or more SMT devices. FIGS. 3E1 and3E2 show an example configuration 40 where solder paste 41 is providedon each of the contact pads 25 on the front surface of the modulesubstrate 20. In some implementations, the solder paste 41 can beapplied to desired locations on the panel (e.g., 16 in FIG. 3A1) indesired amount by an SMT stencil printer.

In block 12 c of FIG. 2, one or more SMT devices can be positioned onthe solder contacts having solder paste. FIGS. 3F1 and 3F2 show anexample configuration 42 where example SMT devices 43 are positioned onthe solder paste 41 provided on each of the contact pads 25. In someimplementations, the SMT devices 43 can be positioned on desiredlocations on the panel by an automated machine that is fed with SMTdevices from tape reels.

In block 12 d of FIG. 2, a reflow operation can be performed to melt thesolder paste to solder the one or more SMT devices on their respectivecontact pads. In some implementations, the solder paste 41 can beselected and the reflow operation can be performed to melt the solderpaste 41 at a first temperature to thereby allow formation of desiredsolder contacts between the contact pads 25 and the SMT devices 43.

In block 12 e of FIG. 2, solder residue from the reflow operation ofblock 12 d can be removed.

In block 12 f of FIG. 2, adhesive can be applied on one or more selectedareas on the module substrate 20 to allow mounting of one or more dies.FIGS. 3G1 and 3G2 show an example configuration 44 where adhesive 45 isapplied in the die-mounting area 23. In some implementations, theadhesive 45 can be applied to desired locations on the panel (e.g., 16in FIG. 3A1) in desired amount by techniques such as screen printing.

In block 12 g of FIG. 2, one or more dies can be positioned on theselected areas with adhesive applied thereon. FIGS. 3H1 and 3H2 show anexample configuration 46 where an example die 36 is positioned on thedie-mounting area 23 by way of the adhesive 45. In some implementations,the die 36 can be positioned on the die-mounting area on the panel by anautomated machine that is fed with dies from a tape reel.

In block 12 h of FIG. 2, the adhesive between the die the die-mountingarea can be cured. Preferably, such a curing operation can be performedat one or more temperatures that are lower than the above-describedreflow operation for mounting of the one or more SMT devices on theirrespective contact pads. Such a configuration allows the solderconnections of the SMT devices to remain intact during the curingoperation.

In block 12 i of FIG. 2, adhesive residue from the mounting operation ofblocks 12 f-12 g can be removed.

In block 12 j of FIG. 2, electrical connections such as wirebonds can beformed between the mounted die(s) and corresponding contact pads on themodule substrate 20. FIGS. 311 and 312 show an example configuration 48where a number of wirebonds 49 are formed between the contact pads 37 ofthe die 36 and the contact pads 24 of the module substrate 20. Suchwirebonds can provide electrical connections for signals and/or power toand from one or more circuits of the die 36. In some implementations,the formation of the foregoing wirebonds can be achieved by an automatedwirebonding machine.

In block 12 k of FIG. 2, a plurality of RF-shielding wirebonds can beformed about a selected area on the module substrate 20. FIGS. 3J1 and3J2 show an example configuration 50 where a plurality of RF-shieldingwirebonds 51 are formed on wirebond pads 26. The wirebond pads 26 areschematically depicted as being electrically connected (dotted lines 31)with one or more reference planes such as a ground plane 30. In someembodiments, such a ground plane can be disposed within the modulesubstrate 20. The foregoing electrical connections between theRF-shielding wirebonds 51 and the ground plane 30 can yield aninterconnected RF-shielding structure at sides and underside of the areadefined by the RF-shielding wirebonds 51. The electrical connectionsbetween the RF-shielding wirebonds 51 and the ground plane 30 caninclude vias 6 and/or one or more racetracks 7, for example, asdescribed with reference to FIG. 1B. As described herein, a conductivelayer can be formed above such an area and connected to upper portionsof the RF-shielding wirebonds 51 to thereby form an RF isolationstructure 2 having an RF-shielded volume.

In the example configuration 50 of FIGS. 3J1 and 3J2, the RF-shieldingwirebonds 51 are shown to form a perimeter around the area where the die(36) and the SMT devices (43) are located. Other perimeterconfigurations are also possible. For example, a perimeter can be formedwith RF-wirebonds around the die, around one or more of the SMT devices,or any combination thereof. In some implementations, anRF-wirebond-based perimeter can be formed around any circuit, device,component or area where RF-isolation is desired.

In the example configuration 50 of FIGS. 3J1 and 3J2, the RF-shieldingwirebonds 51 are shown to have an asymmetrical side profile configuredto facilitate controlled deformation during a molding process asdescribed herein. Additional details concerning such wirebonds can befound in, for example, PCT Publication No. WO 2010/014103 titled“SEMICONDUCTOR PACKAGE WITH INTEGRATED INTERFERENCE SHIELDING AND METHODOF MANUFACTURE THEREOF.” In some embodiments, other shaped RF-shieldingwirebonds can also be utilized. For example, generally symmetricarch-shaped wirebonds as described in U.S. Pat. No. 8,071,431, titled“OVERMOLDED SEMICONDUCTOR PACKAGE WITH A WIREBOND CAGE FOR EMISHIELDING,” can be used as RF-shielding wirebonds in place of or incombination with the shown asymmetric wirebonds. In some embodiments,RF-shielding wirebonds do not necessarily need to form a loop shape andhave both ends on the surface of the module substrate. For example, wireextensions with one end on the surface of the module substrate and theother end positioned above the surface (for connecting to an upperconductive layer) can also be utilized.

In the example configuration 50 of FIGS. 3J1 and 3J2, the RF-shieldingwirebonds 51 are shown to have similar heights that are generally higherthan heights of the die-connecting wirebonds (49). Such a configurationallows the die-connecting wirebonds (49) to be encapsulated by moldingcompound as described herein, and be isolated from an upper conductivelayer to be formed after the molding process.

In block 121 of FIG. 2, an overmold can be formed over the SMTcomponent(s), die(s), and RF-shielding wirebonds. FIG. 3K shows anexample configuration 52 that can facilitate formation of such anovermold. A mold cap 53 is shown to be positioned above the modulesubstrate 20 so that the lower surface 54 of the mold cap 53 and theupper surface 21 of the module substrate 20 define a volume 55 wheremolding compound can be introduced.

In some implementations, the mold cap 53 can be positioned so that itslower surface 54 engages and pushes down on the upper portions of theRF-shielding wirebonds 51. Such a configuration allows whatever heightvariations in the RF-shielding wirebonds 51 to be removed so that theupper portions touching the lower surface 54 of the mold cap 53 are atsubstantially the same height. When the mold compound is introduced andan overmold structure is formed, the foregoing technique maintains theupper portions of the encapsulated RF-shielding wirebonds 51 at or closeto the resulting upper surface of the overmold structure.

In the example molding configuration 52 of FIG. 3K, molding compound canbe introduced from one or more sides of the molding volume 55 asindicated by arrows 56. In some implementations, such an introduction ofmolding compound can be performed under heated and vacuum condition tofacilitate easier flow of the heated molding compound into the volume55.

FIG. 3L shows an example configuration 58 where molding compound hasbeen introduced into the volume 55 as described in reference to FIG. 3Kand the molding cap removed to yield an overmold structure 59 thatencapsulates the various parts (e.g., die, die-connecting wirebonds, andSMT devices). The RF-shielding wirebonds are also shown to besubstantially encapsulated by the overmold structure 59. The upperportions of the RF-shielding wirebonds are shown to be at or close tothe upper surface 60 of the overmold structure 59.

FIG. 3M shows an example panel 62 that has overmold structures 59 formedover the multiple array sections. Each array section's overmoldstructure can be formed as described herein in reference to FIGS. 3K and3L. The resulting overmold structure 59 is shown to define a commonupper surface 60 that covers the multiple modules of a given arraysection.

The molding process described herein in reference to FIGS. 3K-3M canyield a configuration where upper portions of the encapsulatedRF-shielding wirebonds are at or close to the upper surface of theovermold structure. Such a configuration may or may not result in theRF-shielding wirebonds forming a reliable electrical connection with anupper conductor layer to be formed thereon.

In block 12 m of FIG. 2, a top portion of the overmold structure can beremoved to better expose upper portions of the RF-shielding wirebonds.FIG. 3N shows an example configuration 64 where such a removal has beenperformed. In the example, the upper portion of the overmold structure59 is shown to be removed to yield a new upper surface 65 that is lowerthan the original upper surface 60 (from the molding process). Such aremoval of material is shown to better expose the upper portions 66 ofthe RF-shielding wirebonds 51.

The foregoing removal of material from the upper portion of the overmoldstructure 59 can be achieved in a number of ways. FIG. 3O shows anexample configuration 68 where such removal of material is achieved bysand-blasting. In the example, the lighter-shaded portion is wherematerial has been removed to yield the new upper surface 65 and betterexposed upper portions 66 of the RF-shielding wirebonds. Thedarker-shaded portion is where material has not been removed, so thatthe original upper surface 60 still remains. The region indicated as 69is where the material-removal is being performed.

In the example shown in FIG. 3O, a modular structure corresponding tothe underlying module substrate 20 (depicted with a dotted box 22) isreadily shown. Such modules will be separated after a conductive layeris formed over the newly formed upper surface 65.

In block 12 n of FIG. 2, the new exposed upper surface resulting fromthe removal of material can be cleaned.

In block 12 o of FIG. 2, an electrically conductive layer can be formedon the new exposed upper surface of the overmold structure, so that theconductive layer is in electrical contact with the upper portions of theRF-shielding wirebonds. Such a conductive layer can be formed by anumber of different techniques, including methods such as spraying orprinting.

FIG. 3P shows an example configuration 70 where an electricallyconductive layer 71 has been formed over the upper surface 65 of theovermold structure 59. As described herein, the upper surface 65 betterexposes the upper portions 66 of the RF-shielding wirebonds 51.Accordingly, the formed conductive layer 71 forms improved contacts withthe upper portions 66 of the RF-shielding wirebonds 51.

As described in reference to FIG. 3J, the RF-shielding wirebonds 51 andthe ground plane 30 can yield an interconnected RF isolation structureat sides and underside of the area defined by the RF-shielding wirebonds51. With the upper conductive layer 71 in electrical contact with theRF-shielding wirebonds 51, the upper side above the area is now shieldedas well, thereby yielding a shielded volume.

FIG. 3Q shows an example panel 72 that has been sprayed with conductivepaint to yield an electrically conductive layer 71 that covers multiplearray sections. As described in reference to FIG. 3M, each array sectionincludes multiple modules that will be separated.

In block 12 p of FIG. 2, the modules in an array section having a commonconductive layer (e.g., a conductive paint layer) can be singulated intoindividual packaged modules. Such singulation of modules can be achievedin a number of ways, including a sawing technique.

FIG. 3R shows an example configuration 74 where the modular section 20described herein has been singulated into a separated module 75. Theovermold portion is shown to include a side wall 77; and the modulesubstrate portion is shown to include a side wall 76. Collectively, theside walls 77 and 76 are shown to define a side wall 78 of the separatedmodule 75. The upper portion of the separated module 75 remains coveredby the conductive layer 71. As described herein in reference to FIG. 3B,the lower surface 27 of the separated module 75 includes contact pads28, 29 to facilitate electrical connections between the module 75 and acircuit board such as a phone board.

FIGS. 3S1, 3S2 and 3S3 show front (also referred to as top herein), back(also referred to as bottom herein) and perspective views of thesingulated module 75. As described herein, such a module includesRF-shielding structures encapsulated within the overmold structure; andin some implementations, the overall dimensions of the module 75 is notnecessarily any larger than a module without the RF-shieldingfunctionality. Accordingly, modules having integrated RF-shieldingfunctionality can advantageously yield a more compact assembled circuitboard since external RF-shield structures are not needed. Further, thepackaged modular form allows the modules to be handled easier duringmanipulation and assembly processes.

In block 12 q of FIG. 2, the singulated modules can be tested for properfunctionality. As discussed above, the modular form allows such testingto be performed easier. Further, the module's internal RF-shieldingfunctionality allows such testing to be performed without externalRF-shielding devices.

FIG. 3T shows that in some embodiments, one or more of modules includedin a circuit board such as a wireless phone board can be configured withone or more packaging features as described herein. Non-limitingexamples of modules that can benefit from such packaging featuresinclude, but are not limited to, a controller module, an applicationprocessor module, an audio module, a display interface module, a memorymodule, a digital baseband processor module, GPS module, anaccelerometer module, a power management module, a transceiver module, aswitching module, and a power amplifier (PA) module.

FIG. 4A shows a process 80 that can be implemented to assemble apackaged module having one or more features as described herein on acircuit board. In block 82 a, a packaged module can be provided. In someembodiments, the packaged module can represent a module described inreference to FIG. 3T. In block 82 b, the packaged module can be mountedon a circuit board (e.g., a phone board). FIG. 4B schematically depictsa resulting circuit board 90 having module 1 mounted thereon. While onemodule is illustrated as being mounted on the circuit board 90, it willbe understood that one or more other modules can be also be mountedthereon. The circuit board 90 can also include other features such as aplurality of connections 92 to facilitate operations of various modulesmounted thereon.

In block 82 c, a circuit board having modules mounted thereon can beinstalled in a wireless device. FIG. 4C schematically depicts a wirelessdevice 94 (e.g., a cellular phone) having a circuit board 90 (e.g., aphone board). The circuit board 90 is shown to include a module 91having one or more features as described herein. The wireless device isshown to further include other components, such as an antenna 95, a userinterface 96, and a power supply 97.

FIG. 4D schematically depicts a wireless device 94 having a packagedmodule 1, such as a chip or a module. The wireless device 94 can be amobile device, such as a smart phone. The wireless device 94 illustratedin FIG. 4D can include one or more features shown in FIG. 4C, some ofwhich have been omitted from FIG. 4D for illustrative purposes. In someembodiments, the packaged module 1 can include any of the modulesdescribed herein. As illustrated, the packaged module 1 includes an RFcomponent 116 and an RF isolation structure 2 formed about the RFcomponent 116 so as to provide RF isolation properties. The RF isolationstructure 2 can be disposed about the perimeter of the packaged module 1or disposed around the RF component 116 on other suitable areas of thepackaged module 1. The RF isolation structure 2 can provide one or moreRF isolation functionalities such as isolating the RF component 116 froman RF influence (arrow 112) from another device 118 on the electronicdevice 110, isolating the RF component 116 from an external RF source(arrow 114) outside of the electronic device 110, and/or preventingelectromagnetic radiation (arrows 119 a and 119 b) from RF signalsand/or noise from the RF component 116 from reaching the other device118 on the electronic device 110 and/or to an external RF source (notshown) outside of the electronic device 110. The RF component 116 caninclude one or more circuit elements configured to transmit and/orreceive an RF signal. Non-limiting examples of the RF component 116include a power amplifier, a voltage-controlled oscillator, a filter, aswitch, and the like. For instance, in the embodiment illustrated inFIG. 1A, the RF component can include the high band portion 3 and/or thelow band portion 4.

Although one RF component 116 is shown in FIG. 4D, it will be understoodthat two or more RF components can be included within an RF isolationvolume resulting from the RF isolation structure 2. According to someembodiments, the packaged module 1 can include two or more RF componentseach having a dedicated RF isolation structure.

FIG. 5A is a flow diagram of an illustrative process 120 of determininga racetrack layout. Any combination of the features of the process 120or any of the other processes described herein can be embodied in anon-transitory computer readable medium and stored in memory. Whenexecuted by one or more processors, the non-transitory computer readablemedium can cause some or all of the process 120 and/or other processesto be performed. It will be understood that any of the methods discussedherein may include greater or fewer operations. It will also beunderstood that any of the methods discussed herein may includeoperations performed in any order, as appropriate.

The process 120 can determine a layout of a racetrack along theperiphery of a packaged module. The racetrack can be part of an RFisolation structure that forms an RF isolation volume about one or moreRF components of the packaged module. The racetrack can be configured ata ground potential. The racetrack can be formed in one layer or morelayers of a substrate. In some embodiments, the racetrack can be part ofa printed circuit board under an RF component, for example, as shown inFIG. 1B.

The width of the racetrack can be non-uniform. Having a narrower and/orwider racetrack in a selected defined area about the perimeter of apackaged module can tailor the RF isolation structure to the particularneeds of the packaged module. A narrower section of a racetrack and/or abreak in the racetrack can be included in one or more low radiatingareas of the packaged module. Alternatively or additionally, a widersection of racetrack can be included in a hot spot of the packagedmodule. The process 120 can determine one or more selected areas of apackaged module where a section of the racetrack can be widened,narrowed, include a break, or any combination thereof. Customizing theracetrack layout with the process 120 can reduce the overall area of thepackaged module without significantly effecting electromagneticinterference (EMI) performance of the packaged module.

The process 120 can include obtaining EMI data for a module at block122, identifying areas of the module associated with relatively high EMIand/or relatively low EMI at block 124, and determining a racetracklayout at block 126. This process can be iterated any suitable number oftimes to achieve a desired EMI performance.

EMI data can be obtained for a module at block 122. In some embodiments,an electromagnetic scan/probe can be performed to obtain the EMI data.For instance, a near field scan can be performed. The EMI data can beassociated with RF applications. According to certain embodiments, theEMI data can correspond to two or more modes of operation of an RFcomponent of the module. For example, the EMI data can correspond to ahigh band mode of operation and a low band mode of operation, in whichthe RF component operates within a lower frequency band in the low bandmode than in the high band mode of operation. Different RF isolationconsiderations may apply to different frequency bands of operation. Forexample, at higher frequencies, RF signals can have smaller wavelengths.It can be desirable to have a wider racetrack section and/or a racetracksection without a break near high band portions of the module. Asanother example of different modes of operation, the EMI data cancorrespond to a low power mode of operation and a high power mode ofoperation.

The EMI data can correspond to any suitable module configuration. Forinstance, the EMI data can correspond to an unshielded module without anRF isolation structure. As another example, the EMI data can correspondto a module with one or more racetracks having a uniform width. Incertain implementations, the EMI data can correspond to a module havinga racetrack with a maximum racetrack width that can be included in themodule. According to some other implementations, the EMI data cancorrespond to a module having a racetrack with a minimum width of aparticular metal layer of the substrate in which the racetrack isincluded. In another example, the EMI data can correspond to a modulehaving a non-uniform racetrack with one or more breaks, one or moreselected portions narrower, one or more selected portions widened, orany combination thereof.

Areas associated with relatively high and/or relatively low EMI can beidentified at block 124. For instance, an area of a module associatedwith a lowest EMI value can be identified. The area with the lowest EMIvalue can be classified as a low radiating area. As another example, oneor more areas of the module associated with an EMI value below apredefined lower threshold can be identified. An area of the module withan EMI value below the predefined lower threshold can be classified as alow radiating area. Alternatively or additionally, one or more areas ofa module associated with an EMI value above a predefined upper thresholdcan be identified. An area of the module with an EMI value above thepredefined upper threshold can be classified as a hot spot. In yetanother example, an area of the module having the highest EMI value canbe identified. Such an area can be classified as a hot spot.

Areas of the module associated with relatively high EMI can benefit bystronger RF isolation compared to other areas of the module. In someimplementations, an area of the module associated with relatively highEMI can be a hot spot and/or an area for which the RF isolationstructure provides less RF isolation than other areas of the module.Such areas can provide less RF isolation than defined in productspecifications and/or than desired in a particular area. According tosome embodiments, hot spots can occur at or near areas of a module thatgenerate signals with a high power level, such as an output of a poweramplifier (PA) or at an input of a low noise amplifier (LNA).Alternatively or additionally, hot spots can occur at or near areas of apackaged module with a high activity factor, such as an oscillator (forexample, a voltage-controlled oscillator) and/or an LNA.

Areas of the module associated with relatively low EMI can provide asufficient level of RF isolation at or near a break in the racetrackand/or with a relatively thin section of the racetrack. In someimplementations, an area of the module associated with relatively lowEMI can be a low radiating area and/or an area for which the RFisolation structure provides more RF isolation than other areas of thepackaged module. Such areas can provide more RF isolation than definedin product specifications and/or than desired in a particularapplication. In a low radiating area, no signals or only signals with alow power level may be generated. According to some embodiments, a lowradiating area can occur at or near areas of a module through which nosignals propagate or through which signals having only a low power levelpropagate. Alternatively or additionally, low radiating areas can occurat or near areas of a packaged module with a low activity factor.

An RF isolation structure that includes one or more racetracks can begrounded by a connection to a ground plane, for example, by anelectrical connection to a lower conductive layer below an RF componentthat is configured as a ground plane. The ground plane can be includedin the module. While the ground plane ideally has a parasitic inductanceof zero, in reality, the ground plane has a non-zero parasiticinductance. Widening a section of the racetrack can reduce an inductanceassociated with the ground plane. For instance, experimental dataindicate that a racetrack with a uniform width of 140 microns improvedEMI performance by about 2 dBm in certain areas of a module compared toa racetrack with a uniform width of 60 micron in the module. Conversely,narrowing and/or removing a section of the racetrack can increase theinductance of the ground plane. In one or more selected areas of thepackaged module, such as low radiating areas, the racetrack can have abreak and/or be thinned relative to other portions of the racetrackwithout causing significant effects in the performance of the RFisolation structure.

Higher inductance associated with the ground plane can lead to a lessstable RF isolation structure that can affect signals generated by an RFcomponent being isolated by the RF isolation structure. For example, theRF isolation structure can function like an antenna when having arelatively weak connection to the ground plane. This can cause the RFisolation structure to amplify radiation, rather than provide RFisolation. Such an affect can occur at locations of a modulecorresponding to relatively high EMI. When the racetrack is too thin ina section and/or includes too large of a break, the RF isolationstructure can float due to a weak ground connection. The weak groundconnection can cause portions of the module to be associated withrelatively high EMI. Thus, it can be desirable to widen the racetrack inthe portions of the racetrack associated with relatively high EMIrelative to other portions of the racetrack.

At an upper threshold width, widening the racetrack may notsignificantly improve RF isolation. Above the upper threshold width,advantages of widening the racetrack may not provide a significantdecrease in radiated power and consequently RF isolation of the RFisolation structure. As a result, it can be desirable for the racetrackwidth to be below the upper threshold width for particular areas andabove the point at which the RF isolation structure starts to float dueto a weak ground connection. In such a racetrack layout, the racetrackcan also include one or more breaks and/or one or more sections that arenarrowed in selected areas without noticeably impacting RF isolationperformance of the RF isolation structure. These concepts can be used toidentify a racetrack layout tailored to the particular RF isolationneeds of a module. In certain embodiments, a racetrack can haveapproximately a minimum width for satisfying electromagneticinterference requirements of the packaged component, in which the widthof the racetrack is non-uniform.

With continued reference to FIG. 5A, a racetrack layout can bedetermined at block 126. In the racetrack layout, the width of theracetrack in areas associated with high EMI can be greater than thewidth of the racetrack in areas associated with low EMI. For instance,as shown in FIGS. 6B, 6C, and 6F, the racetrack 7 can have one or morebreaks 145 in areas associated with low EMI. As another example, asshown in FIGS. 6D, 6E, and 6F, the racetrack 7 can have one or morenarrowed sections 150 in areas associated with low EMI. In thedetermined racetrack layout, the racetrack width can be sufficientlywide such that the RF isolation structure does not behave like a weakground plane and below an upper threshold above which increasedracetrack width should not significantly improve RF isolation.Additionally, the determined racetrack layout can include at least onebreak and/or narrowed section, for example, as illustrated in FIGS. 6Bto 6G.

By executing the process 120, racetrack layout can be determined suchthat EMI associated with a packaged module meets a specification withoutusing excess area and conductive material for the racetrack.Accordingly, the process 120 can result in a packaged module with aracetrack configured to provide RF isolation with efficient utilizationof die area.

FIG. 5B is a flow diagram of an illustrative process 130 of determininga racetrack layout. The process 130 can be substantially the same as theprocess 120, except that block 124 of the process 120 is replaced withblock 134 in the process 130 and at block 126 racetrack layout can bedetermined based on block 134. Thus, the process 130 can include anycombination of features described earlier with reference to obtainingEMI data at block 122 and/or determining a racetrack layout at block126. The process 130 can include obtaining EMI data at block 122,determining sensitivity of areas of a module to external radiation atblock 134, and determining a racetrack layout at block 126. The process130 can be iterated any suitable number of times. It will be understoodthat, according to certain embodiments, the process 120 and the process130 can be performed together, in serial, in parallel, or anycombination thereof. Thus, determined racetrack layouts can be based ona relative level of EMI associated with area(s) of a module and/or asensitivity of the area(s) of the module to external radiation.

The principles and advantages described in connection with areas of apackaged module associated with relatively low and/or relatively highEMI can be applied to areas of the packaged module that area relativelysensitive and/or relatively insensitive to external radiation at block134. For instance, sensitivity data can be obtained and areas that arerelatively more sensitive to electromagnetic radiation and/or areas thatare relatively less sensitive to electromagnetic radiation can beidentified. In some embodiments, the sensitivity data can include EMIdata and/or data derived from such EMI data. Areas of the packagedmodule that are sensitive to external radiation can be treated similarlyto areas of the packaged module associated with relatively high EMI. Forinstance, at block 126, the racetrack can be widened in areas that areidentified as being sensitive to external radiation at block 134.Alternatively or additionally, areas of the packaged module that are notsensitive to external radiation can be treated similarly to areas of thepackaged module associated with relatively low EMI. For instance, atblock 126, a break can be added to the racetrack and/or the racetrackcan be narrowed in areas that are identified as being insensitive toexternal radiation at block 134. Areas that are sensitive to externalradiation can include, for example, outputs of the module. For instance,an output matching network (OMN) area of a power amplifier module and/oran output of a VCO can be relatively sensitive to external radiation. Bycontrast, areas that are not sensitive to external radiation caninclude, for example, input areas and/or DC paths.

For illustrative purposes, more detail will be provided with referenceto including breaks in the racetrack in selected areas and/or narrowingthe racetrack in selected sections along the periphery of a substrate.Although narrowing and/or including a break in the racetrack isdescribed for illustrative purposes, one or more features describedherein can be applied to widening the racetrack in one or more selectedareas.

FIGS. 6A to 6G show cross sections of racetrack layouts in a substratealong the line 140-140 in FIG. 1B in accordance with certainembodiments. One or more features of the illustrated racetrack layoutscan be applied to one or more racetracks in different layers of asubstrate. The illustrated racetrack layouts can be determined inaccordance with the process 120 and/or the process 130 in someembodiments.

As illustrated in FIGS. 6A to 6G, the racetrack 7 is a conductivefeature formed in the substrate that is configured at a groundpotential. As illustrated, the racetrack 7 is disposed along theperimeter of the packed module 1 in the substrate. The racetrack 7 canbe part of the RF isolation structure that provides an RF isolationvolume about the RF component of the packaged module 1. The racetrack 7can be low loss conductive material with a high conductivity, forexample, copper, gold, or silver. For instance, in certainimplementations, the racetrack 7 is copper.

FIG. 6A shows a top plan view of a cross section of the packaged module1 along the line 140-140 of FIG. 1B. As shown in FIG. 6A, the racetrack7 can have a uniform width. In accordance with the principles andadvantages described herein, the racetrack 7 shown in FIG. 6A can haveapproximately a minimum width required to meet a specification and/orprovide a desired level of RF isolation.

FIG. 6B shows a top plan view of a cross section of the packaged module1 along the line 140-140 of FIG. 1B according to an embodiment. Theracetrack 7 shown in FIG. 6B has a break 145. According to certainimplementations, the break 145 can be included in a low radiating areaof the packaged module 1. For instance, the break 145 can be in an areaof the packaged module 1 with a low activity factor. The break 145 canbe included at an area of the packaged module 1 associated with a lowestEMI value in the EMI data for the packaged module 1. In someimplementations, the break 145 can be included at an area of thepackaged module 1 that is relatively insensitive to external radiation.

FIG. 6C shows top plan view of a cross section of the packaged module 1along the line 140-140 of FIG. 1B according to another embodiment. Theracetrack 7 can have a plurality of breaks in certain embodiments. Forinstance, as shown in FIG. 6C, the racetrack 7 has three breaks 145. Theracetrack 7 can include two or more breaks 145 of substantially the samelength. Alternatively or additionally, the racetrack 7 can include twoor more breaks 145 of different lengths. The breaks 145 can be disposedat low radiating areas of the packaged module 1 and/or at areas of thepackaged module that are relatively insensitive to external radiation.

FIGS. 6D and 6E show other top plan views of a cross section of thepackaged module 1 along the line 140-140 of FIG. 1B according to certainembodiments. Narrowed sections 150 can be disposed at low radiatingareas of the packaged module 1 and/or at areas of the packaged modulethat are relatively insensitive to external radiation. As shown in FIG.6D, the racetrack 7 can include a narrowed section 150. As shown in FIG.6E, the racetrack 7 can include a plurality of narrowed sections 150.For instance, the racetrack 7 can include two or more narrowed sections150 of substantially the same length. Alternatively or additionally, theracetrack 7 can include two or more narrowed sections 150 of differentlengths. The narrowed sections 150 can be thinned on an inner edgefacing the RF component. This can provide additional area for otherfeatures to be included in the substrate in the same layer as theracetrack 7. In certain embodiments, the racetrack 7 can have a width ofapproximately a minimum width of metal layers in a particular layer ofthe substrate in a narrowed section 150. The minimum width of a metallayer in a particular layer of the substrate can be for example, about30 um to about 60 um.

FIG. 6F shows another top plan view of a cross section of the packagedmodule 1 along the line 140-140 of FIG. 1B according to anotherembodiment. As shown in FIG. 6F, the racetrack 7 can include a break 145and a narrowed section 150. The racetrack 7 can include two or morebreaks 145 and one or more narrowed sections 150. The racetrack 7 caninclude one or more breaks 145 and two or more narrowed sections 150.

FIG. 6G shows a top plan view of a cross section of the packaged module1 along the line 140-140 of FIG. 1B according to yet another embodiment.As shown in FIG. 6G, the racetrack 7 can include a conductive line 160that divides areas of the packaged module 1 into separate RF isolationareas. For instance, the conductive line 160 can divide the packagedmodule 1 into a first RF isolation area 170 a and a second RF isolationarea 170 b. Different circuitry can be disposed in the separateisolation areas. In one example, a power amplifier can be in the firstRF isolation area 170 a and one or more filters can be in the second RFisolation area 170 b. As another example, the high band portion 3 ofFIG. 1A can be in the first RF isolation area 170 a and the low bandportion 4 of FIG. 1A can be in the second RF isolation area 170 b. WhileFIG. 6G shows the conductive line 160 dividing the packaged module 1into two separate RF isolation areas, it will be understood that thepackaged module 1 can be divided into more than two separate RFisolation areas in accordance with the principles and advantagesdescribed herein. As illustrated, the conductive line 160 divides thepackaged module 1 into separate RF isolation areas of approximately thesame size. In other implementations, the separate isolation areas canhave different sizes from each other. Conductive features, such aswirebonds, can provide at least a portion of an electrical connectionbetween the conductive line 160 and a conductive layer disposed over thefirst RF portion and/or the second RF portion. The conductive line 160can increase the stability of the racetrack 7 being at a groundpotential. The conductive line 160 can have approximately the same widthas the outer portion of the racetrack 7. The conductive line 160 can beimplemented in accordance with any of principles and advantages of theracetracks 7 described herein.

Packaged modules in accordance with one or more features describedherein can include particular racetrack layouts. For instance, theracetrack can be wider in a first area of the packaged module associatedwith a higher EMI than in a second area of the packaged moduleassociated with a lower EMI. For instance, as shown in FIGS. 6B to 6E, abreak 145 or a narrowed section 150 can be included in the second areaand the first area can have a greater racetrack width. As anotherexample, the racetrack can be widened in the first area compared to thesecond area.

The first area can correspond to a hot spot of the packaged module andthe second area can correspond to a low radiating area of the packagedmodule. For example, the hotspot can be adjacent to a power amplifieroutput or an output of a different RF component that generates a highpower signal. As another example, the hotspot can be adjacent to avoltage-controlled oscillator output or an output of a different RFcomponent that has a high activity factor. By contrast, the second areacan be adjacent to an area of the packaged module with a low activityfactor, an area of the packaged module that does not generate signals,an area of the packaged module in which low power signal propagate, thelike, or any combination thereof. The racetrack can include one or morebreaks 145 and/or one or more narrowed sections 150 in low radiatingareas of a packaged module.

A hotspot in the first area and/or a low radiating area in the secondarea can result from the RF component of the packaged module. Forinstance, one or more RF components being isolated by the RF isolationstructure can emit more radiation to the first area than to the secondarea.

Alternatively or additionally, the first area can be exposed to moreexternal radiation than the second area. For instance, a hot spot of anadjacent component could be adjacent to the first area. The racetrackcan include one or more breaks 145 and/or one or more narrowed sections150 in areas of a packaged module that are relatively insensitive toexternal radiation.

The racetrack layouts described herein can be included in an RFisolation structure of a packaged module that includes one or moreconductive features forming at least a portion of an electricalconnection between the racetrack and a conductive layer above the RFcomponent. As one example, the one or more conductive features caninclude wirebonds, for example, the wirebonds 51 illustrated in FIG. 1B.Alternatively, the one or more conductive features can include a metalcan surrounding the RF component.

In certain embodiments, the RF component within the RF isolation volumeformed by the RF isolation structure includes a power amplifier. Forinstance, the racetrack layouts illustrated in FIGS. 6A to 6G cancorrespond to the packaged module illustrated in FIGS. 1A and 1B.

Some of the embodiments described above have provided examples inconnection with packaged modules and/or electronic devices that includeRF components, such as power amplifiers. However, the principles andadvantages of the embodiments can be used for any other systems orapparatus that have needs for a shielding and/or isolation.

Systems implementing one or more aspects of this disclosure can beimplemented in various electronic devices. Examples of electronicdevices can include, but are not limited to, consumer electronicproducts, parts of the consumer electronic products, electronic testequipment, etc. More specifically, electronic devices configuredimplement one or more aspects of the present disclosure can include, butare not limited to, an RF transmitting device, an RF receiving device,an RF transceiver, any portable device having an RF component (forexample, a power amplifier), a mobile phone (for example, a smartphone), a telephone, a base station, a femtocell, a radar, a deviceconfigured to communicate according to the WiFi and/or Bluetoothstandards, a television, a computer monitor, a computer, a hand-heldcomputer, a tablet computer, a laptop computer, a personal digitalassistant (PDA), a microwave, a refrigerator, an automobile, a stereosystem, a DVD player, a CD player, a VCR, an MP3 player, a radio, acamcorder, a camera, a digital camera, a portable memory chip, a washer,a dryer, a washer/dryer, a copier, a facsimile machine, a scanner, amulti functional peripheral device, a wrist watch, a clock, the like,etc. Part of the consumer electronic products can include a multi-chipmodule including an RF isolation structure, a power amplifier module, anintegrated circuit including an RF isolation structure, a substrateincluding vias that can be used to form part of an RF isolationstructure, the like, or any combination thereof. Moreover, otherexamples of the electronic devices can also include, but are not limitedto, memory chips, memory modules, circuits of optical networks or othercommunication networks, and disk driver circuits. Further, theelectronic devices can include unfinished products.

Unless the context clearly requires otherwise, throughout thedescription and the claims, the words “comprise,” “comprising,” and thelike are to be construed in an inclusive sense, as opposed to anexclusive or exhaustive sense; that is to say, in the sense of“including, but not limited to.” The words “coupled” or connected”, asgenerally used herein, refer to two or more elements that may be eitherdirectly connected, or connected by way of one or more intermediateelements. Additionally, the words “herein,” “above,” “below,” and wordsof similar import, when used in this application, shall refer to thisapplication as a whole and not to any particular portions of thisapplication. Where the context permits, words in the above DetailedDescription using the singular or plural number may also include theplural or singular number respectively. The word “or” in reference to alist of two or more items, that word covers all of the followinginterpretations of the word: any of the items in the list, all of theitems in the list, and any combination of the items in the list.

Moreover, conditional language used herein, such as, among others,“can,” “could,” “might,” “may,” “e.g.,” “for example,” “such as” and thelike, unless specifically stated otherwise, or otherwise understoodwithin the context as used, is generally intended to convey that certainembodiments include, while other embodiments do not include, certainfeatures, elements and/or states. Thus, such conditional language is notgenerally intended to imply that features, elements and/or states are inany way required for one or more embodiments or that one or moreembodiments necessarily include logic for deciding, with or withoutauthor input or prompting, whether these features, elements and/orstates are included or are to be performed in any particular embodiment.

The above detailed description of certain embodiments is not intended tobe exhaustive or to limit the invention to the precise form disclosedabove. While specific embodiments of, and examples for, the inventionare described above for illustrative purposes, various equivalentmodifications are possible within the scope of the invention, as thoseordinary skilled in the relevant art will recognize. For example, whileprocesses or blocks are presented in a given order, alternativeembodiments may perform routines having steps, or employ systems havingblocks, in a different order, and some processes or blocks may bedeleted, moved, added, subdivided, combined, and/or modified. Each ofthese processes or blocks may be implemented in a variety of differentways. Also, while processes or blocks are at times shown as beingperformed in series, these processes or blocks may instead be performedin parallel, or may be performed at different times.

The teachings of the invention provided herein can be applied to othersystems, not necessarily the systems described above. The elements andacts of the various embodiments described above can be combined toprovide further embodiments.

While certain embodiments of the inventions have been described, theseembodiments have been presented by way of example only, and are notintended to limit the scope of the disclosure. Indeed, the novel methodsand systems described herein may be embodied in a variety of otherforms; furthermore, various omissions, substitutions and changes in theform of the methods and systems described herein may be made withoutdeparting from the spirit of the disclosure. The accompanying claims andtheir equivalents are intended to cover such forms or modifications aswould fall within the scope and spirit of the disclosure.

What is claimed is:
 1. A method of determining a racetrack layout, themethod comprising: obtaining electromagnetic interference data for amodule, the electromagnetic interference data being associated with anelectromagnetic probe; identifying one or more low radiating areas ofthe module based on the electromagnetic interference data, the moduleincluding a radio frequency component coupled to a major surface of asubstrate; and determining a racetrack layout based on said identifying,the racetrack being disposed such that the major surface of thesubstrate is between the racetrack and the radio frequency component,the racetrack and a conductive layer forming a portion of a radiofrequency isolation structure around the radio frequency component, andthe radio frequency component being disposed between the conductivelayer and the major surface of the substrate.
 2. The method of claim 1wherein the racetrack layout includes a section with a reduced width ina low radiating area of the one or more low radiating areas relative toa width in other sections of the racetrack layout.
 3. The method ofclaim 1 wherein the racetrack layout includes a break in a low radiatingarea of the one or more low radiating areas.
 4. The method of claim 1wherein the racetrack layout includes a break in a first low radiatingarea of the one or more low radiating areas and a narrowed section in asecond low radiating area of the one or more low radiating areas.
 5. Themethod of claim 1 wherein said obtaining includes performing theelectromagnetic probe.
 6. The method of claim 1 wherein theelectromagnetic interference data corresponds to two or more modes ofoperation of the radio frequency component.
 7. The method of claim 1wherein the electromagnetic interference data corresponds to the modulewithout the radio frequency isolation structure.
 8. The method of claim1 wherein the electromagnetic interference data corresponds to themodule including a different racetrack layout than the racetrack layout.9. The method of claim 1 further comprising iterating said identifyingand said determining.
 10. The method of claim 1 wherein said identifyingone or more low radiating areas includes identifying areas of the moduleconfigured to emit less radiation than other areas of the module. 11.The method of claim 1 wherein said identifying one or more low radiatingareas includes identifying areas of the module configured to receiveless external radiation than other areas of the module.
 12. The methodof claim 1 further comprising determining a second racetrack layoutbased on said identifying, the second racetrack being disposed in adifferent layer of the substrate than the racetrack.
 13. The method ofclaim 1 further comprising forming the racetrack layout.
 14. The methodof claim 1 further comprising additionally identifying areas of themodule that are more sensitive to external radiation and areas of themodule that are less sensitive to external radiation, said determiningbeing based on said identifying and said additionally identifying. 15.The method of claim 1 wherein a low radiating area of the one or morelow radiating areas is associated with a lower activity factor thanother areas of the module.
 16. The method of claim 1 wherein the radiofrequency component includes a power amplifier.
 17. The method of claim6 wherein the two or more modes include a low power mode and a highpower mode.
 18. The method of claim 6 wherein the two or more modesinclude a low band mode and a high band mode.
 19. The method of claim 1wherein the racetrack layout includes a first narrowed section in afirst low radiating area of the one or more low radiating areas and asecond narrowed section in a second low radiating area of the one ormore low radiating areas.
 20. The method of claim 1 wherein theracetrack layout includes a first break in a first low radiating area ofthe one or more low radiating areas and a second break in a second lowradiating area of the one or more low radiating areas.